0W-40 or 5W-50?
02-14-2007, 09:16 PM
#61
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Join Date: Feb 2005
Location: Andover, NY
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Sorry,
I don't post here often. But what 1999Porsche911 really upsets me. Please do not continue spreading jibberish and confusing other good intentioned people by claiming that they are incorrect. As a physicist I am not an expert on heat transfer engineering but I do have something of a knowledge of thermodynamics. Heat is transfered faster with higher flow rates until frictional forces overcome (well beyond the scope of our discussion) following
dQ = kMdT, st k>0
where M is the mass flow rate. The reason that your finger doesn't get burned is not because of the speed in the flame but rather the time in the flame. My colleague is currently recommending that by your logic you can run through a large fire. He also suggests that it may be best if you try this experiment. Have you ever used a fan? Surprisingly when the fan is on it cools better. If one continues to be hot one changes the setting on the fan such that it is transferring more mass by increasing the air velocity rather than turning the fan down. This is to note by
dT/dt=-r(deltaT), st r>0
such that two masses in thermal equilibrium do not transfer heat. I do not wish to spend any more time but it is clear that your first supposition is clearly inverse to the truth rendering the rest of your argument null.
I wish common sense was more common.
I don't post here often. But what 1999Porsche911 really upsets me. Please do not continue spreading jibberish and confusing other good intentioned people by claiming that they are incorrect. As a physicist I am not an expert on heat transfer engineering but I do have something of a knowledge of thermodynamics. Heat is transfered faster with higher flow rates until frictional forces overcome (well beyond the scope of our discussion) following
dQ = kMdT, st k>0
where M is the mass flow rate. The reason that your finger doesn't get burned is not because of the speed in the flame but rather the time in the flame. My colleague is currently recommending that by your logic you can run through a large fire. He also suggests that it may be best if you try this experiment. Have you ever used a fan? Surprisingly when the fan is on it cools better. If one continues to be hot one changes the setting on the fan such that it is transferring more mass by increasing the air velocity rather than turning the fan down. This is to note by
dT/dt=-r(deltaT), st r>0
such that two masses in thermal equilibrium do not transfer heat. I do not wish to spend any more time but it is clear that your first supposition is clearly inverse to the truth rendering the rest of your argument null.
I wish common sense was more common.
Last edited by sketchers356; 02-14-2007 at 09:41 PM.
